reverse (mutable only)

diff --git a/Data/Vector/MVector.hs b/Data/Vector/MVector.hs
index e4ed39a..a7306d8 100644 (file)
--- a/Data/Vector/MVector.hs
+++ b/Data/Vector/MVector.hs
@@ -16,7 +16,7 @@
 module Data.Vector.MVector (
   MVectorPure(..), MVector(..),
 
-  slice, new, newWith, read, write, copy, grow, unstream, map, update
+  slice, new, newWith, read, write, copy, grow, unstream, update, reverse, map
 ) where
 
 import qualified Data.Vector.Stream      as Stream
@@ -30,7 +30,7 @@ import GHC.Float (
     double2Int, int2Double
   )
 
-import Prelude hiding ( length, map, read )
+import Prelude hiding ( length, reverse, map, read )
 
 gROWTH_FACTOR :: Double
 gROWTH_FACTOR = 1.5
@@ -201,6 +201,25 @@ unstreamUnknown s
                                  . double2Int
                                  $ int2Double (length v) * gROWTH_FACTOR
 
+update :: MVector v m a => v a -> Stream (Int, a) -> m ()
+{-# INLINE update #-}
+update v s = Stream.mapM_ put s
+  where
+    {-# INLINE put #-}
+    put (i, x) = write v i x
+
+reverse :: MVector v m a => v a -> m ()
+{-# INLINE reverse #-}
+reverse v = reverse_loop 0 (length v - 1)
+  where
+    reverse_loop i j | i < j = do
+                                 x <- unsafeRead v i
+                                 y <- unsafeRead v j
+                                 unsafeWrite v i y
+                                 unsafeWrite v j x
+    reverse_loop _ _ = return ()
+
+
 map :: MVector v m a => (a -> a) -> v a -> m ()
 {-# INLINE map #-}
 map f v = map_loop 0
@@ -212,10 +231,4 @@ map f v = map_loop 0
                                write v i (f x)
                | otherwise = return ()
 
-update :: MVector v m a => v a -> Stream (Int, a) -> m ()
-{-# INLINE update #-}
-update v s = Stream.mapM_ put s
-  where
-    {-# INLINE put #-}
-    put (i, x) = write v i x
 

diff --git a/Data/Vector/MVector/Mut.hs b/Data/Vector/MVector/Mut.hs
index 2b453a4..8c7cd1c 100644 (file)
--- a/Data/Vector/MVector/Mut.hs
+++ b/Data/Vector/MVector/Mut.hs
@@ -3,7 +3,7 @@
 #include "phases.h"
 
 module Data.Vector.MVector.Mut (
-  Mut(..), run, unstream, map, update
+  Mut(..), run, unstream, update, reverse, map
 ) where
 
 import qualified Data.Vector.MVector as MVector
@@ -11,7 +11,7 @@ import           Data.Vector.MVector ( MVector )
 
 import           Data.Vector.Stream ( Stream )
 
-import Prelude hiding ( map )
+import Prelude hiding ( reverse, map )
 
 data Mut a = Mut (forall m mv. MVector mv m a => m (mv a))
 
@@ -19,15 +19,23 @@ run :: MVector mv m a => Mut a -> m (mv a)
 {-# INLINE run #-}
 run (Mut p) = p
 
+trans :: Mut a -> (forall m mv. MVector mv m a => mv a -> m ()) -> Mut a
+{-# INLINE trans #-}
+trans (Mut p) q = Mut (do { v <- p; q v; return v })
+
 unstream :: Stream a -> Mut a
 {-# INLINE_STREAM unstream #-}
 unstream s = Mut (MVector.unstream s)
 
-map :: (a -> a) -> Mut a -> Mut a
-{-# INLINE_STREAM map #-}
-map f (Mut p) = Mut (do { v <- p; MVector.map f v; return v })
-
 update :: Mut a -> Stream (Int, a) -> Mut a
 {-# INLINE_STREAM update #-}
-update (Mut p) s = Mut (do { v <- p; MVector.update v s; return v })
+update m s = trans m (\v -> MVector.update v s)
+
+reverse :: Mut a -> Mut a
+{-# INLINE_STREAM reverse #-}
+reverse m = trans m (MVector.reverse)
+
+map :: (a -> a) -> Mut a -> Mut a
+{-# INLINE_STREAM map #-}
+map f m = trans m (MVector.map f)
 

diff --git a/Data/Vector/Stream.hs b/Data/Vector/Stream.hs
index d52f8df..c10450c 100644 (file)
--- a/Data/Vector/Stream.hs
+++ b/Data/Vector/Stream.hs
@@ -495,3 +495,4 @@ foldM m z (Stream step s _) = foldM_go z s
                      Skip    s' -> foldM_go z s'
                      Done       -> return z
 
+